Seating elements in form of a seat and a backrest, or of a combination of a seat and a backrest, come in a variety of forms, shapes, and structures. It is common that seating elements are adapted to fit closely those parts of the human body that are resting on the seat. For example, the backrest is formed to accommodate the human back by being bent in the shape of the human spine.
To improve seating comfort and to improve ergonomics, modern seats and chairs feature shape adjustment means, which allow adjusting the shape of the seating elements to the needs of the user. For example, the inclination and curvature of the backrest may be changed, or a lumbar support may be personal adjusted, in order to most ergonomically support the user that is in contact with the seating element. The shape adjustment means known from the prior art, however, require actuation by hand. Once the shape has been set by the user, it stays more or less constant until the shape adjustment means is again actuated by the user. Thus, it is usually a time-consuming process until a user has found a comfortable position, as such a position has to be found by trial and error.
In order to overcome this problem, a different approach is taken in DE 199 16 411 A1 and also in EP 002 50 109 A1. In both documents, a skeleton or framing is described which is capable of reacting to a load applied on said skeleton by actively and automatically deforming against the action of said load. Although use of this skeleton is primarily intended for aerodynamics, it is also described that the skeleton may also be used for seating elements.
It should be noted that structures, which look similar to the skeleton of DE 199 16 411 A1 and EP 002 50 109 A1 are known from aerodynamics. The only purpose of these aerodynamic structures, however, is to provide a body of which the shape can be changed manually using actuators. For example, in EP 0 860 355 A1, a landing flap section is described. Using mechanical actuators, the camber of the section may be changed. In FR 2 715 124 A1 and LU 88 528 A1, sailing structures are shown, of which the camber may be adjusted by rotation of the leading edge.
In contrast to the self-adjusting structure described in DE 199 16 411 A1 and EP 002 50 109, however, the structures of EP 0 860 355 A1, FR 2 715 124 A1, and LU 88 528 A1 require actuators to effect a shape change.
Starting from DE 199 16 411 A1 and EP 002 50 109, it is one object of the invention to adapt the structure described in these documents for further improving the ergonomics of seating elements.
Moreover, it is an object of the invention to provide a seating element that is easy to manufacture.
Finally, it is an object of the invention to provide a seating element that is easily adjusted to various human body shapes.